Bottom-up superconducting and Josephson junction devices inside a group-IV semiconductor

TL;DR

This paper proposes a novel approach to create superconducting devices within silicon or germanium crystals using atomistic fabrication, enabling new quantum device architectures and potentially advancing solid-state quantum technology.

Contribution

It introduces a method to fabricate superconducting devices directly inside semiconductor crystals, combining superconductivity with quantum properties of epitaxial semiconductors.

Findings

Superconducting wires and Josephson junctions are feasible within doped silicon/germanium.

The approach enables integration of superconductivity with quantum semiconductor devices.

Potential for improved or new quantum device functionalities.

Abstract

Superconducting circuits are exceptionally flexible, enabling many different devices from sensors to quantum computers. Separately, epitaxial semiconductor devices such as spin qubits in silicon offer more limited device variation but extraordinary quantum properties for a solid-state system. It might be possible to merge the two approaches, making single-crystal superconducting devices out of a semiconductor by utilizing the latest atomistic fabrication techniques. Here we propose superconducting devices made from precision hole-doped regions within a silicon (or germanium) single crystal. We analyze the properties of this superconducting semiconductor and show that practical superconducting wires, Josephson tunnel junctions or weak links, superconducting quantum interference devices (SQUIDs), and qubits are feasible. This work motivates the pursuit of "bottom-up" superconductivity for improved or fundamentally different technology and physics.